Distracted a little by the Adonis-like figure standing in front but it does appear to be an
Auto Union/Horch 901 type 40, 'Kfz.15' would cover it but identical front ends can be seen on some 'Kfz.17' types so it's often less confusing to ignore the overall kfz numbers when referring to a specific vehicle.
The German name for the overall chassis class that these medium cars came into was the rather magnificent:
'Mittlere gelandegangige Einheits-personenkraftwagen' or 'm.gl.E.Pkw.'....
(or as the British would rather less fulsomely have had it: 'Car, Medium, 4X4')
Outside of the rivet-counting world, I'd just call it a 'Horch medium'.
Cheers,
Adam.